1. Field of the Invention
The invention relates to a touch keyboard, and more particularly to a capacitive touch keyboard.
2. Description of the Related Art
Referring to FIG. 1, a conventional capacitive touch keyboard defines a plurality of press key zones 15 on a touch panel 1, and a controller 11 determines which one of the press key zones 15 is touched mainly based on a sensed touch signal from the touch panel 1. The touch panel 1 has an insulating substrate 10, and a first indium tin oxide (ITO) conductive layer and a second ITO conductive layer disposed on the insulating substrate 10 (on different surfaces or overlap on a same surface of the insulating substrate 10). The first ITO conductive layer includes a plurality of first electrode lines X1˜Xm arranged in a first direction, and each of the first electrode lines X1˜Xm includes a plurality of first electrodes 12 connected in series. The second ITO conductive layer includes a plurality of second electrode lines Y1˜Yn arranged in a second direction transverse to the first direction. Each of the second electrode lines Y1˜Yn includes a plurality of second electrodes 13 connected in series, and each of the second electrodes 13 is separated from adjacent one of the first electrodes 12.
For such array-type touch structure, the first electrode lines X1˜Xm and the second electrode lines Y1˜Yn must be uniformly and densely disposed on the surface of the touch panel 1 in order to sense a touch signal from each position of the touch panel 1, thus resulting in more electrode lines. However, for a touch keyboard, while positions of the press keys are fixed, i.e., sensing of areas out of the press key zones 15 on the touch panel 1 is not needed, the controller 11 still detects the whole touch panel 1 when determining whether specific press key zones 15 are touched. Moreover, touch zones and coordinates corresponding to each of the press key zones 15 need to be preset, thus increasing loadings and difficulty of the identification.